This invention relates to mixtures of disperse azo dyes.
A known azo dye is C.I. Disperse Orange 37 of the formula 
This dye is disclosed, for example, in CH-A-0406481. Commercially, the dye has been mixed with other dyes to give different shades. However, this dye has been found to act as a skin irritant.
Mixtures of azo dyes are also disclosed in DE-A-4304744 and BE-A-0592096.
DE-A-4304744 discloses dye mixtures containing
(a) 10 to 90 wt % of one or more azo dyes of the formula 
xe2x80x83wherein Y1 is absent or is C1-6 alkyl, C1-6 alkoxy or optionally substituted C1-8 alkylamino or C3-4 alkenylamino and each of Y2 and Y3 independently is hydrogen or optionally substituted C1-6 alkyl;
(b) 10 to 90 wt % of (b1) an azo dye component of the formula 
xe2x80x83and optionally (b2) an azo dye component of the formula 
xe2x80x83in which dye component (b1) is present in an amount of 50 to 100 wt %, and dye component (b2) is present in an amount of 0 to 50 wt %, of component (b); and
(c) 0 to 70 wt % of one or more azo dyes of the formula (c1) or (c2) 
xe2x80x83in which Rc1 is a nitro or C1-6 alkylsulphonyl group optionally substituted by hydroxy;
each of Rc2 and Rc3 independently is absent or is chlorine or bromine;
each of Rc4 and Rc5 independently is absent or is chlorine;
each of Rc6 and Rc7 independently is hydrogen or is an optionally substituted C1-4 alkyl or phenyl group or when Rc2 and Rc3 are absent or are chlorine, Rc6 and Rc7 may additionally be cyanoethyl.
BE-A-0592096 discloses dyes of the formula 
wherein
XD is hydrogen* or is chlorine, bromine, cyano, trifluoromethyl or nitro.
YD is hydrogen*, chlorine, bromine or low molecular weight alkyl;
UD exemplified as hydrogen* or methyl (no other definition given);
ZD is hydrogen* or low molecular weight alkyl;
RD1 is low molecular weight alkyl, alkoxyalkyl or acyloxyalkyl;
mD is zero or 1;
nD is zero or 1; and
the value of RD2 is such that when nD is zero and mD is 1, RD2 is acyloxyalkyl while when mD is zero and nD is 1, RD2 is cyanoethyl.
BE-A-0592096 also discloses mixtures of dyes of the above formula (d) in which, specifically nD is zero, mD is 1, YD is NHCOCH3 and RD2 is acyloxyalkyl with dyes of the formula (e) 
wherein
VE is hydrogen*, chlorine or bromine;
WE is chlorine, bromine, cyano or trifluoromethyl;
RE4 is hydrogen*, methyl, ethyl or chlorine; and
R1 is low molecular weight alkyl, alkyloxyalkyl or acyloxyalkyl.
* Although BE-A-0592096 refers to xe2x80x9chydrogenxe2x80x9d as being a possible substituent for each of UD, XD, YD, ZD, VE and RE4, it seems clear that this is intended merely to indicate the absence of such a substituent. 
It is pointed out that there is no disclosure, in BE-A-0592096, of dyes of the formula (e) wherein each of VE and WE is a chlorine or bromine atom and RE1 is a low molecular weight alkyl group.
Surprisingly, we have found a range of dye mixtures in which the components do not cause any noticeable skin irritation and which provide at least one of excellent heat fastness, high colour strength and excellent build-up characteristics.
Thus, the present invention provides a dye mixture comprising at least
(1)
(A) at least one azo dye of the formula (I) 
xe2x80x83wherein
each of X and X1 independently is chlorine or bromine;
R1 is absent or is C1-4 alkyl; and
each of R2 and R3 independently is hydrogen, C1-6 alkyl or cyanoethyl; but
when R1 is absent, R2 is n-butyl or cyanoethyl and R3 is cyanoethyl; and
(B) at least one azo dye of the formula (II) 
xe2x80x83wherein
X2 is absent or is chlorine or bromine;
each of R4 and R5 independently is hydrogen, C1-4 alkyl, allyl or cyloxyalkyl;
R6 is C1-4 alkyl or NHCOY, in which Y is hydrogen, C1-4 alkyl, or NH2; and
R7 is C1-4 alkoxy; and
at least when, in the formula (I), R1 is absent and, in the formula (II), X2 is bromine, R6 is NHCOY (in which Y is methyl), R7 is methoxy and each of R4 and R5 is allyl or one of R4 and R5 is allyl and the other is hydrogen
(C) at least one azo dye of the formula (III) 
xe2x80x83wherein
X3 is absent or is chlorine or bromine;
R8 is C1-4 alkyl or NHCOY, in which Y is hydrogen, C1-4 alkyl or NH2; and
each of R9 and R10 independently is hydrogen, C1-4 alkyl, allyl or acyloxyalkyl; or
(2)
(A) at least one azo dye of the formula (I), given and defined above, wherein R1 is absent, R2 is n-butyl or cyanoethyl and R3 is cyanoethyl; and
(D) at least one azo dye of the formula (IV) 
xe2x80x83wherein
R11 is absent or is C1-4 alkyl;
R12 is hydrogen, cyano, hydroxyl, OCOR14 or OCOOR14 in which R14 is C1-4 alkyl, aryl or aralkyl;
R13 is hydroxyl, OCOR14 in which R14 is as defined above; and each of m and n independently is 1, 2, 3 or 4.
Alkyl groups may be straight-chained or branched and be for example methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec. butyl or tert.-butyl. This applies as well to alkyl groups in acyloxyalkyl, alkoxy and aralkyl residues. Acyl in acyloxyalkyl is preferably COY wherein Y is C1-4 alkyl. Aryl is preferably phenyl and naphthyl. Aralkyl is preferably benzyl and phenethyl.
In one preferred range of dye mixtures embodying the invention, the dye of the formula (I) has the formula 
in which each of X and X1 independently is chlorine or bromine and R2 is n-butyl or cyanoethyl, and the mixture additionally contains a dye of the formula (II), given and defined above and optionally a dye of the formula (III), also given and defined above.
In such a dye mixture, an especially preferred dye of the formula (I)1 has the formula (1) 
Such a dye does not cause irritation to the skin and lends to the mixture excellent heat fastness.
Especially when the mixture contains a dye of the formula (I)1, given and defined above, a preferred dye of the formula (II) in the mixture has the formula (II)1 
in which X2 is chlorine or bromine and R7 is methoxy or ethoxy.
It is not necessary to include, in a mixture containing the dyes of the formulae (I)1 and (II)1, a dye of the formula (III) but such a dye may be added when a different shade is required.
A dye mixture of dye components of the respective formulae (I)1 and (II)1 preferably contains from 15-75% inclusive of the dye of the formula (I)1 and from 25-85% inclusive of the dye of the formula (II)1, more preferably from 30-60% inclusive of the dye of the formula (I)1 and from 40-70% inclusive of the dye of the formula (II)1, by weight of the weight of the mixture of dyes of the formulae (I)1 and (II)1.
On the other hand, when, in a dye mixture containing dye components of the formula (II)1 a dye of the formula (III) is additionally present, this dye component preferably has the formula (III)1 
in which X3 is chlorine or bromine, Y is methyl or ethyl and each of R9 and R10 independently is ethyl or allyl.
In such a dye mixture, the dye of the formula (II) is preferably a dye (II)2 in which X2 is chlorine, each of R4 and R5 independently is ethyl, allyl or acetoxyethyl, R6 is the group NHCOY (in which Y is methyl or ethyl) and R7 is C1-6 alkoxy.
In an especially preferred dye mixture embodying the invention in the formula (I)1, R1 is absent, R2 is n-butyl, R3 is cyanoethyl and each of X and X1 is chlorine; in the formula (II), X2 is bromine, R6 is the group NHCOY (in which Y is methyl), R7 is methoxy and each of R4 and R5 is allyl; and, in the formula (III)1, X4 is bromine, R8 is the group NHCOY (in which Y is methyl) and each of R9 and R10 is ethyl.
A dye mixture containing each of dye components of the respective formulae (I)1, (II) and (III)1 preferably contains, by weight of the weight of the mixture of dyes of the formulae (I)1, (II) and (III)1,
from 5-50% inclusive of the dye of the formula (I);
from 5-75% inclusive of the dye of the formula (II); and
from 5-75% inclusive of the dye of the formula (III);
and more preferably
from 5-25% inclusive of the dye of the formula (I);
from 15-50% inclusive of the dye of the formula (II); and
from 30-60% inclusive of the dye of the formula (III).
In an alternative the preferred range of dye mixtures embodying the invention, in the dye of the formula (I), R1 is C1-4 alkyl, more preferably methyl. Such dyes are referred to below as dyes (I)2. A preferred such dye has the formula (2) 
Such a dye provides especially high colour strength to dye mixtures embodying the invention, especially mixtures which are black in colour.
Especially when the mixture contains a dye (I)2, a preferred dye of the formula (II) in the mixture has the formula 
in which X2 is chlorine or bromine and R7 is methoxy or ethoxy.
It is not necessary to include, in a mixture containing the dyes of the formulae (I)2 and (II)1 a dye of the formula (III) but such dyes may be added when a different shade is required.
A dye mixture of dye components of the respective formulae (I)2 and (II)1 preferably contains from 15-75% inclusive of the dye of the formula (I)2 and from 25-85% inclusive of the dye of the formula (II)1, more preferably from 30-60% inclusive of the dye of the formula (I)2, and from 40-70% inclusive of the dye of the formula (II)1, by weight of the weight of the mixture of the dyes of formulae (I)2 and (II)1.
On the other hand, when, in a dye mixture containing dye components of the formula (I)2 and (II)1, a dye of the formula (III) is additionally present, this dye component preferably has the formula (III)2 
wherein X3 is chlorine or bromine and each of R9 and R10 independently is ethyl or allyl.
In such a dye mixture, the dye of the formula (II) is preferably a dye (II)2 in which X2 is chlorine, each of R4 and R5 independently ethyl, allyl or acetoxyethyl, R6 is the group NHCOY (in which Y is methyl or ethyl) and R7 is C1-6 alkoxy.
In an especially preferred dye mixture embodying the invention, in the formula (I)2, each of X and X1 is chlorine, R1 is methyl, R2 is ethyl and R3 is cyanoethyl; in the formula (II)2, X2 is chloro, each of R4 and R5 is allyl, R6 is the group NHCOY (in which Y is methyl) and R7 is methoxy; and in the formula (III)2, X3 is chloro and each of R8 and R9 is ethyl.
A dye mixture containing each of dye components of the respective formula (I)2, (II)2 and (III)2 preferably contains, by weight of the weight of the mixture of the dyes of the formulae (I)2, (II)2 and (III)2,
from 5-50% inclusive of the dye of the formula (I)2;
from 5-75% inclusive of the dye of the formula (II)2; and
from 5-75% inclusive of the dye of the formula (III)2;
and more preferably
from 5-25% inclusive of the dye of the formula (I)2;
from 15-50% inclusive of the dye of the formula (II)2; and
from 30-60% inclusive of the dye of the formula (III)2.
In yet another preferred range of dye mixtures embodying the invention, the dye of the formula (I) has the formula 
in which each of X and X1 independently is chlorine or bromine and R2 is n-butyl or cyanomethyl and the mixture additionally contains a dye of the formula (IV), given and defined above.
In such a dye mixture, an especially preferred dye of the formula (I)1 has the formula 
Such dye mixtures containing dye components of the formulae (I) and (IV) have particularly good build-up characteristics.
In an especially preferred dye mixture embodying the invention, in the formula (I)1, each of X and X1 is chlorine, R1 is absent, R2 is n-butyl, and R3 is cyanoethyl; and, in the formula (IV), R11 is hydrogen, R12 is cyano, R13 is acetoxy and each of m and n is 2.
A dye mixture containing each of dye components of the respective formulae (I)1 and (IV) preferably contains from 10-90% inclusive of the dye of the formula (I)1 and from 10-90% inclusive of the dye of the formula (IV), by weight of the weight of the mixture of dyes of the formulae (I)1 and (IV) and more preferably from 25-75% inclusive of the dye of the formula (I)1 and from 25-75% inclusive of the dye of the formula (IV).
All dyes of the formulae (I)-(IV) can be prepared in a conventional manner by diazotising and coupling.
Thus, dyes of the formula (I) may be prepared by diazotising an amine of the formula (V) 
wherein each of X and X1 independently is a chlorine or bromine atom, and coupling the diazotised amine to a coupling component of the formula (VI) 
wherein each of R1, R2 and R3 is as defined above.
Dyes of the formula (II) maybe prepared by diazotising an amine of the formula (VII) 
wherein X2 is absent or is chlorine or bromine, and coupling the diazotised amine to a coupling component of the formula (VIII) 
wherein each of R4, R5, R6 and R7 is as defined above.
Dyes of the formula (III) may be prepared by diazotising an amine of the formula (IX) 
wherein X3 is absent or is chlorine or bromine, and coupling the diazotised amine to a coupling component of the formula (X) 
wherein each of R8, R9 and R10 is as defined above.
Dyes of the formula (IV) may be prepared by diazotising an amine of the formula (XI) 
and coupling the diazotised amine to a coupling component of the formula (XII) 
wherein each of R11, R12, R13, m and n is as defined above.
In the above diazotisation and coupling reactions, the diazotisation is carried out using a diazotising agent, which is preferably nitrosyl sulphuric acid, optionally diluted with glacial acetic acid or a phosphoric/acetic acid mixture and preferably at a temperature of 0-10xc2x0 C., more preferably 0-5xc2x0 C. and preferably at a pH less than 1 (say 0.5) up to 7, more preferably 0.5-1, followed by a subsequent increase in pH to 3-4 to isolate the dye.
A mixture embodying the invention of (1) at least one dye of the formula (I) (Component A), at least one dye of the formula (II) (Component B) and optionally at least one dye of the formula (III) or (2) at least one dye of formula (I) (Component A) and at least one dye of the formula (IV) (Component D) may additionally comprise at least one other dye (Component E), especially a yellow, greenish yellow, orange, red or brown dye capable of producing a navy or black shade. Preferably such other dyes are present in an amount by weight of up to (but no more than) 10%, more preferably 2-6%, of the total colour.
Especially in mixtures for providing a black colour using a mixture of dyes of the formula (I), (II) and (III), it is preferable to add a greenish yellow dye, which may be present in an amount of up to 10%, more preferably 2-6%, by weight of total dye colour and which, typically, may be 5-(2xe2x80x2-nitro)phenylazo-6-hydroxy-4-methyl-3-cyano-N-ethyl pyrid-2-one or 5-(2xe2x80x2,3xe2x80x2-dichloro)phenylazo-6-hydroxy-4-methyl-3-cyano-N-methylpyrid-2-one.
Mixtures embodying the invention can be prepared, for example, by mixing the dye components in the required amounts. Suitable mixing methods include
(1) Co-crystallisation
Typically, the dyes are dissolved in a hot solvent, for example, by placing the dyes in a suitable solvent and heating up to the reflux temperature of the solvent until the dyes are dissolved,
thereafter filtering to provide a solution, and then allowing the solution to cool and crystals to form. The resultant mixture may then undergo further processing, such as milling and spray drying. Examples of suitable solvents for this process are organic solvents such as aromatic hydrocarbons, chlorinated hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, alcohols, amides, sulphoxides, esters, ketones and ethers. Specific examples of organic solvents are toluene, ethyl cellosolve, acetone, chlorobenzene, pyridine, dimethyl formamide, dimethylsulphoxide, ethyl acetate, benzene, tetrahydrofuran and cyclohexane.
Co-crystallisation is generally unsuitable for mixtures containing more than two components.
(2) Co-milling
(a) The dyes are mixed and then milled together to give an intimate blend which is then spray dried to give a solid mixture; or
(b) each dye is milled separately and then mixed in the required ratio before spray drying.
(3) Dry Blending
Each dye is spray dried separately and then mixed in the required ratio by a dry blending process.
Mixtures embodying the invention provide especially useful disperse dyes valuable for colouring synthetic textile materials and fibre blends thereof by exhaust dyeing, padding or printing, and may be formed into dispersions for this purpose. They may also be used in, for example, ink jet printing of textiles and non-textiles, dye diffusion, thermal transfer printing and in the colouration of plastics.
A particular aspect of the invention provides a composition comprising a mixture of (1) dyes (I), (II) and optionally (III) or (2) dyes (I) and (IV), and optionally at least one other disperse dye and, additionally, optionally at least one further ingredient conventionally used in colouring applications such as a dispersing agent, surfactant or wetting agent. The composition typically comprises from 1% to 65%, preferably 10 to 60%, more preferably 20 to 55%, of the total dye mixture in a liquid, preferably an aqueous, or solid medium. Liquid compositions are preferably adjusted to pH 2 to 7, more preferably pH 4 to 6.
Typical examples of dispersing agent are lignosulphonates, naphthalene sulphonic acid/formaldehyde condensates and phenol/cresol/sulphanilic acid/formaldehyde condensates, typical examples of wetting agent are alkyl aryl ethoxylates which may be sulphonated or phosphated and typical example of other ingredients which may be present are inorganic salts, de-foamers such as mineral oil or nonanol, organic liquids and buffers. Dispersing agents may be present at from 10% to 200% on the weight of the dye mixtures. Wetting agents may be used at from 0% to 20% on the weight of the dye mixtures.
The compositions may be prepared by bead milling the dye mixture with glass beads or sand in an aqueous medium. The compositions may have further additions of dispersing agents, fillers and other surfactants and may be dried, by a technique such as spray drying, to give a solid composition comprising from 5% to 65% of dyestuff.
According to another aspect, the invention provides a process for colouring a synthetic textile material or fibre blend thereof which comprises applying to the synthetic textile material or fibre blend a mixture comprising (1) at least one dye of the formula (I), at least one dye of the formula (II) and optionally at least one dye of the formula (III) or (2) at least one dye of the formula (I) and at least one dye of the formula (IV).
The synthetic textile material may be selected from aromatic polyester, especially polyethylene terephthalate, polyamide, especially polyhexamethylene adipamide, secondary cellulose acetate, cellulose triacetate, and natural textile materials, especially cellulosic materials and wool. An especially preferred textile material is an aromatic polyester or fibre blend thereof with fibres of any of the above mentioned textile materials. Especially preferred fibre blends include those of polyester-cellulose, such as polyester-cotton, and polyester-wool. The textile materials or blends thereof may be in the form of filaments, loose fibres, yarn or woven or knitted fabrics.
The mixtures of dyes of formulae (I), (II) and (III) or (I) and (IV), optionally in conjunction with other disperse dyes may be applied to the synthetic textile materials or fibre blends by processes which are conventionally employed in applying disperse dyes to such materials and fibre blends.
Suitable process conditions may be selected from the following
(i) exhaust dyeing at a pH of from 4 to 6.5, at a temperature of from 125xc2x0 C. to 140xc2x0 C. for from 10 to 120 minutes and under a pressure of from 1 to 2 bar, a sequestrant optionally being added;
(ii) continuous dyeing at a pH of from 4 to 6.5, at a temperature of from 190xc2x0 C. to 225xc2x0 C. for from 15 seconds to 5 minutes, a migration inhibitor optionally being added;
(iii) direct printing at a pH of from 4 to 6.5, at a temperature of from 160xc2x0 C. to 185xc2x0 C. for from 4 to 15 minutes for high temperature steaming, or at a temperature of from 190xc2x0 C. to 225xc2x0 C. for from 15 seconds to 5 minutes for bake fixation with dry heat or at a temperature of from 120xc2x0 C. to 140xc2x0 C. and 1 to 2 bar for from 10 to 45 minutes for pressure steaming, wetting agents and thickeners (such as alginates) of from 5 to 100% by weight of the dye optionally being added;
(iv) discharge printing (by padding the dye on to the textile material, drying and overprinting) at a pH of from 4 to 6.5, migration inhibitors and thickeners optionally being added;
(v) carrier dyeing at a pH of from 4 to 6.5, at a temperature of from 95xc2x0 C. to 100xc2x0 C. using a carrier such as methylnaphthalene, diphenylamine or 2-phenylphenol, sequestrants optionally being added; and
(vi) atmospheric dyeing of acetate, triacetate and nylon at a pH of from 4 to 6.5, at a temperature of 85xc2x0 C. for acetate or at a temperature of 90xc2x0 C. for triacetate and nylon for from 15 to 90 minutes, sequestrants optionally being added.
In all the above processes, the dye mixture is applied as a dispersion comprising from 0.001% to 6, preferably from 0.005 to 4%, of the dye mixture in an aqueous medium.
In addition to the above-mentioned application processes, the dye mixtures may be applied to synthetic textile materials and fibre blends by ink-jet printing, the substrates optionally having been pre-treated to aid printing. For ink-jet applications, the application medium may comprise water and a water-soluble organic solvent, preferably in a weight ratio of 1:99 to 99:1, more preferably 1:95 to 50:50 and especially in the range 10:90 to 40:60. The water-soluble organic solvent preferably comprises a C1-4-alkanol, especially methanol or ethanol, a ketone, especially acetone or methyl ethyl ketone, 2-pyrrolidone or N-methylpyrrolidone, a glycol, especially ethylene glycol, propylene glycol, trimethylene glycol, butane-2,3-diol, thiodiglycol or diethylene glycol, a glycol ether, especially ethylene glycol monomethyl ether, propylene glycol monomethyl ether or diethylene glycol monomethyl ether, urea, a sulphone, especially bis-(2-hydroxyethyl) sulphone or mixtures thereof.
The dye mixtures may also be applied to textile materials using supercritical carbon dioxide, in which case the dye formulating agents may optionally be omitted.
Embodiments of the present invention will now be described in more detail with reference to the following Examples, in which parts are by weight unless otherwise stated.